The present invention is related to solar arrays and power distribution systems used therewith.
Solar arrays typically include a plurality of individual solar cells arranged in a series-parallel connection to provide an output having the desired voltage and current characteristics. For example, a first plurality of solar cells connected in series (forming a column of series-connected solar cells) provide an output voltage equal to the sum of the voltage provided by each of the individual series-connected solar cells. The desired voltage magnitude is achieved by connecting a sufficient number of solar cells in series with one another. Connecting a plurality of the series-connected columns in parallel with one another provides the desired current characteristic of the solar array.
A typical solar array is a two-terminal device. The plurality of series-connected solar cells are connected between a positive terminal and a neutral or ground terminal. The voltage generated by the solar array is equal to the sum of the voltage generated by each of the plurality of series-connected solar cells. The voltage generated by the solar array is represented by the difference in potential between the positive terminal and the neutral terminal. In this arrangement, because the second terminal is connected to ground, the voltage at the positive terminal relative to ground is equal to the total voltage generated by the solar array.
In some high-voltage applications the voltage generated by the solar array and therefore provided at the positive terminal relative to ground may be quite large (e.g., 150 volts (V) or more). Voltages of these magnitudes relative to ground become problematic in some applications such as in space, wherein the voltage at the positive terminal interacts with the approximately neutral surrounding environment (e.g., free-floating electrons and/or ions). The potential difference between the positive terminal and the approximately neutral surrounding environment results in detrimental interactions between the solar array and the environment such as arc faults, surface charging and discharging, and/or ion sputtering. A consequence of these interactions is a negative impact on performance and/or life of the solar array.